Rotary well bit



April 1939. A. c. (JATLAND 2,154,032

ROTARY WELL B IT Filed July 10, 19:57

2 Sheets-Sheet l 4&1 Q

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April 11, 1 3 v A. c. CATLAND I ROTARY WELL BIT 2 Sheets-Sheet 2 I Filed July 10, 1937 fire/r/x" 9097:; 69/2/4440 Patented Apr. 11, 1939 UNITED STATES PATENT OFFICE ROTARY BIT Application July 10, 1937, Serial No. 152,975

10 Claims.

This invention relates to a drilling tool and relates more particularly to a bit for usein the rotary method of well drilling. A general object of this invention is to provide a gyratory bit that 5 is rapid in its penetration of the earth formation.

Another object of this invention is to provide an improved gyratory well bit embodying roller rock cutters mounted and related to be particularly efficient in operation.

Another object of. this invention is to provide a well bit embodying a cutter head supported on the shank for rotation about an inclined'axis and a plurality of roller cutters on the head rtatable about axes radiating from and inclined with respect to the axis of rotation of the head.

Another object of this invention is to provide a well bit of the character mentioned in which the cutters have teeth formed and arranged to assure the rotational progression of the cutters 20 and to have a rapid cutting action.

Another object of this invention is to provide a gyratory well bit embodying a novel bearing means for rotatably supporting the cutter head on the shank.

A further object of this invention is to pro vide a bit of the character mentioned in which the bearing parts and the cuttersmay be easily and quickly replaced when worn.

The various objects and features of my invention will be fully understood from the following detailed description of a typical preferred form and application of the invention, throughout which description reference is made to the accompanying drawings, in .which:

Fig. 1 is a side elevation of the bit provided by this invention. Fig. 2 is an enlarged bottom elevation of the cutter head illustrating the cutters in broken lines. Fig. 3 is a transverse detailed sectional view taken as indicated by line 33 on 40 Fig. 4 and Fig. 4 is an enlarged vertical detailed sectional view of the head and. the adjacent parts of the shank.

The gyratory well bit provided by this invention includes, generally, a body or shank ID to be connected with the lower end of a rotary well drilling string, a cutter holder or head ll supported on the lower end of the shank I II for rotation about an axis inclined with respect to the vertical axis of the shank and a. plurality of spaced roller cutters l2 supported on the head H for rotation about their individual axes.

The shank Ill may be an elongate, generally cylindrical member provided at its upper end with means for connection with the drilling .string. In the case illustrated this means comprises a tapered screw threaded pin l3 projecting from the upper end of the shank. In accordance with the invention the lower portion ID of the shank I0 is offset and inclined relative to the central vertical axis of the shank Ill. The lower end l4 of the shank Ill is inclined being normal to the longitudinal axis of the inclined shank portion Hl In the preferred construction the longitudinal axis of the shank I0 intersects the axis of the inclined portion Ill adjacent the plane of the lower end M. A cylindrical socket l5 of substantial depth enters the shank portion H) from the lower end [4 and is co-axial with the inclined axis of the portion III. A central longitudinal fluid passagel6 extends into the shank l 0 from its upper end.

The cutter holder or cutter head H is supported at the lower end of the shank It] for rota tion about an inclined axis with respect to the shank. The head I l is provided at its upper end with a reduced stem I! which is rotatably supported in the socket l5 by the bearing means to be hereinafter described. An upwardly facing annular shoulder I8 is provided on the head II at the base of the stem H. The lower portion or major portion of the head II is formed to receive and support the cutters l2. The head II has a plurality of spaced downwardly and outwardly projecting legs l9. In the preferred construction there are three equally circumferentially spaced legs IS. The inner surfaces 20 of the legs I9 are flat and inclined downwardly; and outwardly relative to the longitudinal axis of the head II. The body of the head II is provided with fiat surfaces 2| opposing and substantially parallel with the surfaces 20 of the legs IS. The spaces between the opposing surfaces 20 and 2| form pockets for receiving the cutters l2. The lower outer corners of thelegs l9 are preferably bevelled off.

The means for rotatably'supporting the head II on the shank I0 is preferably an anti-friction bearing means. The bearing means includes a sleeve or thimble 22 of inverted cup shape arranged on the stem IT. The thimble 22 bears on the upper end of the stem I1 and its lower end bears on the shoulder I 8.' The thimble 22 is secured to the head ll so that it may be removed for replacement when worn. In the particular structure illustrated in the drawings the thimble 22 is welded to the shoulder l8 at 23 in such a manner that it may be easily "removed for replacement. The thimble 22 is provided with a plurality of ball races. The upper end of the thimble 22 has an annular groove or ball race 24.

faces upwardly. Two axially or longitudinally spaced ball races 25 and 26 are provided in the side or periphery of the thimble 22.

The bearing means further includes a sectional ball retainer or bearing cage enclosing the thimble 22. The cage includes an upper section 21 which has the shape of an inverted cup. The upper end of the cage section 21 is recessed in the upper wall of the socket I5 to be maintained centralized relative tothe socket and the stem IL The internal upper wall of the section 21 has an annular ball race 26 opposing the race 24. A series of balls 29 cooperates with the opposing races 24 and 28 for the transmission of vertical thrusts or axial thrusts between the thimble 22 and the cage section 21. The bearing cage further includes a tubular section 36 having its upper end bearing on the lower end of the section 21 and a second tubular section 3| whose upper end bears on the lower end of the section 36. Grooves are cut in the adjacent inner corners of the sections 21 and 30 and register to form an annular ball race 32 that opposes the race 25 of the thimble 22. Similar grooves are cut in the adjacent inner corners of the cage sections 36 and 3| to form a ball race 33 which opposes the race 26 of the thimble 22. the opposing races 25 and 32 and a series of balls 35 is provided in the opposing races 26 and 33. The balls 34 and 35 transmit the radial loads or forces between the thimble 22 and the bearing cage. The balls 34 and 35 may also take some of the axial loads and serve to prevent downward separation of the head II from the bearing cage and the shank I6.

Means is provided to retain the above described bearing cage in' the socket I5 and thus retain the rotatable head II on the shank I6. This means comprises a tubular nut or sleeve 36 threaded in the socket I5 from its lower end. The internal surface of the sleeve 36 engages or cooperates with the "external surfaces of the cage sections 21,

36 and 3| whereby the sleeve 36 centralizes the cage sections and transmits the lateral or radial loads from the cage 'sections to the shank I6. The sleeve 36 is provided at its lower end with'an inwardly projecting flange 31 which cooperates with the lower end of the cage section 3| to 'retain the several cage sections in the socket I5 and thus hold the head II and the associated parts against downward separation from the shank I6. Notches 38 may be provided in the lower end of the sleeve 36 to facilitate its turning or unthreading. It will be observed that the head II is supported on the lower end of the shank I6 for rotation, with a minimum of friction, about an axis inclined with respect to the axis of the shank. The wearing parts of the bearing means supporting the head II on the shank I6 are all readily removable for replacement,

The cutters I2 are carried by the pitched and rotatable head II for rotation about their individual axes. There is a cutter I2 supported between each pair of opposing surfaces 26 and 2| for rotation about an inclined but generally transverse axis. It is a feature of the invention that the cutters I2 are in the form of toothed roller cutters mounted and designed to have particularly effective cutting engagement with the earth formation. The cutters I2 may be alike in size and shape. The cutters I2 are provided with flat opposite ends and central longitudinal openings 39. In the particular form of the invention A series of balls 34 is provided in The race 24 is co-axial with the stem I1 and illustrated the cutters I2 are frusto-conical having pitched or taperedperlpheral outlines as best illustrated in Fig. 2 the drawings. Cutting teeth 46 are provided hn the peripheries of the roller cutters I2. Thetteeth 46 are preferably comparatively lar; e andadeep. In accordance with the inventioh he cutter teeth 46 .are sharply pitched or haveia steep angle. The teeth 46 formed or arraiiged in this manner have their principal cutting edges 4| extending circumferentially as 'well as axially of the cutters I2.

Anti-friction bearing means are provided for rotatably supporting the cutters I2. Cutter supporting pins 42 are passed inwardly through openings 43 in the legs I9 and are threaded into sockets 44in the head II. The pins 42 have heads 42 received in the openings ,43 and the heads may be welded or peened into openings 43 to lock the pins 42 against unthreading. The

openings 43 and the sockets 44 lie in planes that areradial relative to the axis'of rotation of the 'head II and the longitudinal axes of the openings 43 and the sockets 44 are inclined downwardly and inwardly relative to the axis of the head.

The pins 42 pass through the openings 39 of the cutters I2 and bearing parts are provided on the pins to rotatably support the cutters. Thrust washers or bearing washers 45 are provided on the pins 42 and bear on the surfaces 26 of the legs I9. .Lugs 46 are provided on the lower edges of the washers 45 and are welded to the lower ends of the legs I9 to prevent rotation of the washers. Thrust washers 41 are provided on the pins 42 and bear against the surfaces 2| of the head II. The washers 41 have lugs 48 at their lower ends welded to the head I I to prevent turning of the washers. are received in the end portions of the cutter openings 39. A bearing sleeve or bushing 56 is provided on each pin' 42 between the spaced is provided with axially or longitudinally spaced .ball races 5|. The adjacent ends of the washers 45 and the bushings 56 are provided with grooves which register to form ball races 52. The adjacent ends of the washers 41 and the bushings 56 have registering grooves which form ball races 53. The races 52 and 53 each directly oppose a race 5| of the surrounding cutter I2. Series of balls 54 are arranged in theopposing races 5| and 52 and series of balls 55 are provided in the opposing races 5| and 53. The balls- 54 and 55 rotatably support the cutters I2 for free rotation with a minimum of friction. The balls 54 and 55 transmit radial thrusts as well as end thrusts in both directions, the races 5|, 52 and 53 being of such depth that the balls may transmit all of the thrusts imposed on the cutters. The cutters I2 mounted as just described project downwardly beyond the inclined lower end of the tilted head II and project laterally beyond the sides of the legs I9 to act on the earth formation at the bottom of the well bore. The cutters I2 are supported for independent rotation about axes inclined downwardly and inwardly relative The washers 45 and 41 a passage l6 and extends downwardly through the inclined portion I0 of the shank ID to the socket IS. A central opening '58 extends through the assembled cage section 21 and thimble 22 and a central longitudinal opening 59 extends through the stem l'l into the head II. A wash pipe is threaded in the lower end of the port 51 and extends downwardly through the opening 58 and into the opening 59. The pipe 60 extends through a substantial portion of the opening 59 and cooperates with its wall to prevent the leakage of fluid through the bearing means of the rotatable head II. A distributing chamber 6| is provided in the head II at the lower end oi.the opening 59. Ports 62 extend from the chamber 6| to the spaces between .the legs I9 and the head- II and beans or nozzles 63 are set in the ports 62. The nozzles 63 discharge streams of circulation fluid under pressure downwardly against the adjacent cutters l2. A port 64 of reduced diameter extends downwardly through the head H from the chamber 6| to the lower end of the head. A nozzle 65 may be provided in the lower end of the port 64 to discharge a stream of circulation fluid downwardly from the lower end of the head.

In operation the shank Ill of the internal bit is secured to the lower end of the well drilling string and the bit is rotated in the well in the usual manner. The cutters i2 act on or engage the formation at the bottom of the well bore and their engagement with the formation effects the turning of the cutters about their individual axes and offers resistance to turning of the head II. The engagement of the cutters l2 with the earth formation causes turning of the head H on its own axis at a slower rate of rotation than the shank [0. The head ll being supported for rotation about an axis inclined with respect to the axis of rotation of the shank i0 wobbles or gyrates in the well bore. The head II is supported on the shank in through an efiective antifriction bearing means and is free to rotate with a minimum of friction. The cutters it! projecting from the tilted lower end of the gyrating head 10 are alternately brought into rolling and cutting engagement with the formation at the bottom of the well bore raising and plunging the cutters with the head if and thereby effect turning of the cutters I2 about their individual axes. Accordingly, the teeth 40 are effective in producing the rotational progression of the cutters whereby the cutters are particularly effective in their cutting action and the teeth are successively brought into their cutting positions. The cutters l2 mounted as described above have a generally downwardly directed action on the earth formation although their cutting teeth 40 may act on the side wall of the bore adjacent its bottom when the cutters are in their outermost positions with respect to the center of the bore. Circulation fluid is pumped downwardly through the drilling string to discharge from the nozzles 63 and 65. The fluid discharging from the nozzles 63 eflectively-fiushes the cutters l2 clear of mud and cuttings and the fluid discharging from the nozzle 65 assists in maintaining an eflective agitation of the fluid at the bottom of the bore and may erode the formation at the bottom of the well.

Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

Having described'my invention, I c1aim:

1, A rotary well drilling bit comprising a shank, a cutter head at the lower end of the shank, means mounting the head on the shank for rotation about an axis inclined with respect to the longitudinal axis of the shank, a plurality of toothed roller cutters, and means supporting the cutters on the head for rotation about axes that lie in planes substantially radial with respect to the axis of rotation of the head.

2. A rotary well drilling bit comprising a shank, a cutter head at the lower end of the shank, means-mounting the head on the shank for rotation about an axis inclined with respect to the longitudinal axis of the shank, a plurality of toothed roller cutters, and means supporting the cutters on the head for rotation about axes that lie in planes substantially radial with respect to the axis of rotation of the head and that are inclined with respect to the axis of rotation of the head.

3. A rotary well drilling bit comprising a shank, a cutter head at the lower end of the shank,

means mounting the head on the shank for rotation about an axis inclined with respect to the.

longitudinal axis of the shank, a plurality of toothed roller cutters, and means supporting the cutters on the head to project downwardly therefrom and to rotate about axes inclined downwardly and inwardly and in planes substantially radial with respect to the axis of rotation of the head. i

4. A rotary well drilling bit comprising a shank, a cutter head at the lower end of the shank, means mounting the head on the shank for rotation about an axis inclined with respect to the longitudinal axis of the shank, a plurality of toothed roller cutters, and means supporting the cutters on the head for rotation about axes inclined downwardly and-inwardly relative to the axis of rotation of the head and that lie in planes substantially radial with respect to the axis of rotation of the head.

5. A rotary well drilling bit comprising a shank, a cutter head at the lower end of the shank, means mounting the head on the shank for rotation about an axis inclined with respect to the longitudinal axis of the shank, a plurality of roller cutters, helically pitched teeth on the peripheries of the cutters, and means supporting the cutters for rotation about inclined axes lying in planes substantially radial relative to the axis of rotation of the head where the cutters project beyond the lower end of the head.

6. A rotary well drilling bit comprising a shank, a cutter head at the lower end of the shank, means mounting the head on the shank for rotation about an axis inclined with respect to the longitudinal axis of the shank, a plurality of frusto-conicalroller cutters, cutting teeth on the cutters, and means supporting the cutters on the head for rotation about axes inclined downwardly and inwardly relative tothe ,axis of rotation of the head and that lie in planes substantially 1 to the axis of the shank including balls trans- 7; A rotary well bit comprising a shank having a socket in its lower end, the longitudinal axis of the socket being inclined relative to the longitudinal axis of the shank, ahead having a stem extending into the socket, means supporting the head for rotation about an axis inclined relative mitting end thrusts between the end of the stem and the upper wall of the socket, and balls transmitting radial thrusts between the stem and the side wall of the socket, and cutters rotatably supported by the head.

8. A rotary well bit comprising a shank having a socket in its lower end, the longitudinal axis of the socket being inclined relative to the longitudinal axis of the shank, a head having a stem extending into the socket, means supporting the head for rotationabout an axis inclined relative to the axis of the shank including a bearing cage in thesocket, balls bearing between the upper end of the stern and the cage for transmitting end thrusts inv one direction between the stem and the cage, and balls bearing between the cage and the side of the stem transmitting radial thrusts and,

end thrusts in the other direction between the stem and the cage, and cutters rotatably carried by the head.

9. A rotary well bit comprising a shank having a socket in its lower end, the longitudinal axis of the socket being inclined relative to the longitudinal axis of the shank, a head having a stem extending into the socket, means supporting the head for rotation about'an axis inclined relative to the axisof the shank including a bearing cage in the socket, balls bearing between the upper end of the stem and the cage for transmitting end thrusts in one direction between the stem and the cage, and balls bearing between the cage and the side of the stem transmitting radial thrusts and end thrusts in the other direction between the stem and the cage, spaced roller cutters carried by the head for rotation about their axes and to project from the lower end of the head, and means for conducting fluid through the shank, stem and head and for discharging separate streams of fluid against the cutters.

10. A rotary well drilling bit comprising a shank, a cutter head at the lower end of the shank, means mounting the head on the shank for rotation about an axis inclined with respect to the longitudinal axis of the shank, the head having a downwardly projecting central part and circumferentially spaced downwardly projecting legs spaced outwardly from the central part, pins extending between the legs and the central part,

and cutters on the pins between the legs and central part rotatable about axes inclined with respect to the axis of rotation of the head and projecting downwardly beyond the central part and legs to act on the earth formation.

ALFRED C. CA'I'LAND. 

